How USB Ports Work

USB 2.0 and 3.0

The standard for USB version 2.0 was released in April 2000 and serves as an upgrade for USB 1.1.

USB 2.0 (High-speed USB) provides additional bandwidth for multimedia and storage applications and has a data transmission speed 40 times faster than USB 1.1. To allow a smooth transition for both consumers and manufacturers, USB 2.0 has full forward and backward compatibility with original USB devices and works with cables and connectors made for original USB, too.

Supporting three speed modes (1.5, 12 and 480 megabits per second), USB 2.0 supports low-bandwidth devices such as keyboards and mice, as well as high-bandwidth ones like high-resolution webcams, scanners, printers and high-capacity storage systems. The deployment of USB 2.0 allowed PC industry leaders to forge ahead with the development of PC peripherals to complement existing high-performance PCs. In addition to improving functionality and encouraging innovation, USB 2.0 increases the productivity of user applications and allows the user to run multiple PC applications at once or several high-performance peripherals simultaneously.

The USB 3.0 (SuperSpeed USB) standard became official on Nov. 17, 2008 [source: Everything USB]. USB 3.0 boasts speeds 10 times faster than USB 2.0 at 4.8 gigabits per second. It's meant for applications such as transferring high-definition video footage or backing up an entire hard drive to an external drive. As hard drive capacity grows, the need for a high-speed data transfer method also increases.

Adoption of the USB 3.0 standard has been slow. Chip manufacturers must design motherboard hardware that supports USB 3.0. Computer owners have the option to purchase cards that they can install in their computers to give USB 3.0 support. But hardware support is just part of the problem -- you also need support from your operating system. Even though Microsoft announced that Windows 7 would eventually support the USB 3.0 standard, the company shipped its operating system without USB 3.0 support. Recent distributions of the Linux operating system support USB 3.0.

You might not think data transfer cables create controversy. But some reporters, such as ZDNet writer Adrian Kingsley-Hughes, suggests that one reason USB 3.0 adoption has been slow is because Intel has delayed production on motherboards with USB 3.0 support purposefully to give one of its own products a head start [source: Kingsley-Hughes]. That product is Light Peak, a data transfer technology that has an initial top data transfer speed of 10 gigabits per second with future theoretical speeds reaching 100 gigabits per second. Since Intel is a major manufacturer of chips, only a few computers with motherboards made by other companies currently support USB 3.0.

Intel representatives deny such claims. Company executives have said that the Light Peak technology isn't going to replace USB ports and that both Light Peak and USB 3.0 will work together. In the meantime, you can find computers and accessories that incorporate USB 3.0 on the market today.

For more information on USB and related topics, check out the links on the next page.